On timescales of several years to several decades, weather and climate patterns depend not only on the anthropogenic rise of greenhouse gas concentrations in the atmosphere, but also on natural climate variability. Natural climate variability is both internal – ultimately induced by weather in both atmosphere and ocean – and forced – caused by solar variability and volcanic eruptions. Owing to the chaotic nature of the internal variability, its predictability horizon is limited. But the clear signal of decadal-timescale variability in almost all climate records suggests that, if we are able to observe the phase and amplitude of the current decadal variability “event”, we can exploit the memory of the climate system to predict the further evolution of this event. How to turn this potential for decadal climate prediction into realised predictive skill is the grand challenge of the BMBF-funded project MiKlip.
The decadal climate prediction group comprises the development of the central decadal prediction system, one of the key objectives of MiKlip. Based on the experience previously gained at MPI-M the aim is to continuously improve the prediction system by incorporating latest model improvements and technical requirements to perform an ensemble of forecasts. An example is the implementation of an assimilation plus ensemble generation method based on the experience gained during NWP. Also of importance is the implementation of an ensemble based prediction experiment infrastructure that incorporates a work flow management specified for a large number of simulations including data assimilation and ensemble generation. In the context of the development of predictions for decadal timescales the prediction system is furthermore considered and evaluated for seasonal forecasts. This is attached to the decadal climate prediction group and is in cooperation with the IFM Hamburg and DWD as a joint contribution to EUROSIP.